Cultured human corneal epithelial stem/progenitor cells derived from the corneal limbus.

Stem/progenitor cells of the human corneal epithelium are present in the human corneal limbus, and several corneal epithelial stem/progenitor cell markers have been reported. Recently, the neurotrophin family receptors were reported to be useful markers of corneal epithelial stem/progenitor cells. Therefore, we examined an enzymatic separation method for obtaining corneal epithelial stem/progenitor cells and measuring the change in the expression of low-affinity neurotrophin receptor p75 (p75(NTR)), a receptor belonging to the neurotrophin family. As a result, it was found that our separation method preserved cell viability. Furthermore, p75(NTR) was mainly observed in epithelial basal cells as were the corneal epithelial stem/progenitor markers p63 and integrin β1. p75(NTR) was also observed in the cultured cells, but its frequency decreased with passage. In conclusion, we propose that our culture method will enable the culture of corneal stem cells and that it is a useful tool for elucidating the molecular basis of the niche that is necessary for the maintenance of epithelial stem cells in the corneal limbus. Furthermore, we conclude that p75(NTR) is a useful cell marker for evaluating the characteristics of stem/progenitor cells in culture.